Questions on the design and materials used to connect pieces together using bolts.
Questions tagged [bolting]
84 questions
10
votes
4 answers
Many small bolts, or few large bolts?
I am affixing a servo motor with a machined enclosure to a base plate with drilled holes. The current design uses eight M-2.5 bolts in a figure U pattern (3-2-3) around the enclosure.
Tightening that many bolts/screws takes time, and the small gauge…
Jon Watte
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8
votes
4 answers
What bolts should I specify with Weathering Steel?
When using weathering steel (COR-TEN) on a project, what sort of bolts should I be using?
I have yet to see fixings made of weather steel; presumably because the way it uses a sacrificial layer to form a protective rust coating makes it unsuitable…
thomasmichaelwallace
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8
votes
1 answer
Can nuts safely be removed from bolts where the threads have been intentionally damaged?
On old bridge plans I have occasionally seen a note to "burr threads after installation". This was done to keep the nuts of bolted connection from loosening all the way and falling off of the bolt.
An example of this practice can be seen in this…
hazzey
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7
votes
1 answer
Are standard structural bolts acceptable for all cold climates?
The specifications for standard (ASTM A 325) bolts do not list minimum service temperatures. I am thinking of outdoor applications like Alaska or Canada (lows of -60F) and wondering if the cold temperatures would have an effect on the bolts.
There…
hazzey
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7
votes
3 answers
What method can I use to make a pivot point in an aluminum linkage?
I recently had a project where I made an aluminum linkage (similar to a scissor lift) operated by linear actuators. Aluminum pieces were fabricated from 6061 "standard" aluminum stock, 6mm (0.25 inch) thick. The bars are at most 750x75mm (30x3").…
JYelton
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6
votes
7 answers
Fixing a blind bolt hole when the first 2-3 threads are ruined?
One of my suspension bolts came undone while I was mountain biking recently, sadly I didn't notice. I landed a big drop with only 2-3 threads left engaged, and unsurprisingly it's ruined them.
The rest of the threads (another 20 or so) are fine. …
Codemonkey
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5
votes
2 answers
What could be the downsides of leaving twist-off bolt splines in the interior of exterior columns?
I have a project where the contractor is using ASTM F1852 Tension Control (twist-off) bolts. The project is outdoors and uses weathering steel and weathering fasteners. The main members are hollow steel sections that are utilizing bolted splices.…
hazzey
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5
votes
3 answers
What causes a fastener to lock?
I am rebuilding a car engine. With some of the fasteners I am unscrewing, I notice that a lot of torque is required to undo the fastener. It feels like a snap when undoing a fastener, rather than a smooth twist. If I tighten the fastener to a set…
tgun926
- 153
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5
votes
1 answer
Are stress concentrations a concern when replacing rivets with high strength bolts?
A common method of repairing old riveted structures is to replace any damaged rivets with new high strength bolts.
When this is done, the new bolts are typically installed like they would be on a new structure which results in a bolt pretension. My…
hazzey
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5
votes
1 answer
Do bolts become tighter or looser at cryogenic temperature?
In general, will screws tightened at room temperature become tighter or looser at very low temperature (5 K)?
On the one hand, the screw should loosen because it will contract radially, while the surrounding material will contract slightly less (or…
ninemileskid
- 151
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4
votes
2 answers
Effect of varying diameter bolts on shear stress under eccentric loading
In my mechanics of materials class we are required to be able to solve problems with bolts in shear. Unfortunately our textbook doesn't cover this subject we only had a little bit of information given on slides and I am having trouble finding other…
Devin Crossman
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4
votes
3 answers
Can I use a wooden flat screw head with a washer to mimick a pan head screw?
For example - I am installing a fold up table from Ikea, it needs to hang from the wall, as shown below.
It explicitly says to use pan head instead of flat screw heads like shown in the picture, I would drill into hollow concrete and will use nylon…
appwizcpl
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3
votes
1 answer
What is the purpose of drilled washers?
I was browsing this website and noticed that they have drilled washers.
I could start to guess that the purpose of drilled washers may involve reducing weight by removing material (although this would compromise its structural integrity and ability…
Steven Lu
- 131
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3
votes
1 answer
How often do you need to check torques on bolted flanges?
Due to the fact that pipe flanges rely on bolts, and bolts rely on friction, it seems obvious to me, as a manufacturer of piping, to recommend that bolt torques need to be checked every so often, to ensure piping doesn't leak. I've got a few…
Mark
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3
votes
3 answers
Measuring pipe bolt torque without a torque wrench
I've had trouble with leaky pipe flanges, since my flanges are made of plastic. The problem comes down to the fact that sealing a flange is based on torque. Torque relies on bolt friction, which can change even between different bolt diameters.…
Mark
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